Strippable protective films are applied temporarily to such a manufactured article as metal components, plastics products or rubber products for the purposes of preventing it from scratch, contamination or corrosion at the time when it is processed, transported or stored. The films of the type are required to have such characteristics that after they have been applied temporarily to the above-mentioned manufactured article and have fulfilled the above-mentioned purposes, they are capable of being stripped therefrom readily and integrally.
Heretofore, there have been used resin compositions for strippable protective films, said resin compositions containing their principal components, for examples, ethylene/vinyl acetate copolymers (hereinafter abbreviated to EVA) or ethylene/.alpha.-olefin copolymers having a low crystallinity. While these resin compositions have favorable initial adhesive properties, they involve such drawbacks that because of their poor heat resistance, films prepared therefrom increase in adhesive force during a long-term storage thereof, particularly when they are held under the circumstances of high temperature, and sharply deteriorate in strippability.
Japanese Patent Publn. No. 45974/1983 proposes strippable protective films of polyolefin obtained by improving heat resistance of EVA films.
Although the heat resistance of the proposed films has been improved, however, there were such problems that the films increase in adhesive force due to change on standing when they are stored for a long period of time, or when they are stripped from articles to which they are applied, bleeding matters remain on the surface of the articles.
The present invention is intended to solve such problems associated with the prior art as mentioned above, and accordingly an object of the invention is to provide strippable protective films which are excellent in flexibility, scratch resistance and heat resistance and, at the same time, which have appropriate initial adhesive force to articles to which they are applied and strippability therefrom and, moreover, which are less in change on standing even when they are stored for an extended period of time and are free from bleeding on the article surface when they are stripped therefrom, and compositions therefor.